This invention relates to pressure control valves, and particularly to devices which provide pressure relief limits. More particularly, the invention relates to devices for limiting the valve stem travel of a pressure control valve for insuring against overpressuring a hydraulic fluid system.
Numerous devices have been utilized for the purpose of limiting pressure adjustments via threaded valve stems. For example, one such device provides for a sleeve positioned over a threaded stem wherein the stem is adjusted during assembly and testing of the valve to a desired position, and the sleeve is then crimped to the stem to insure against relative movement thereafter between stem and sleeve. This device has been unsatisfactory to the extent that the crimp has occasionally failed and permitted movement between stem and sleeve. Other devices have involved the use of pins which have been secured in holes in the stem. However, the drilling of holes in the stems has required transfers from a work station to a drill press for drilling of the stems. Such extra handling is undesirable in the mass manufacture of valve assemblies.
Thus, a relatively simple, inexpensive apparatus is desired which requires no extra handling and which is very difficult to alter once assembled. Such an apparatus is particularly desirable for hydraulic applications wherein excess pressure may cause mechanical damage or bodily harm.